Application Of Pathological Three-Dimensional Reconstruction In Margins Assessment And Radiotherapy Adjustment Of Breast Conserving Surgery

Objective:The purpose of this study was to reconstruct the original three-dimensional conformation of tumor resection tissue through the study of breast-conserving surgery(BCS)excision specimens for part-mount sub-serial section(PMSS)and pathological three-dimensional(3D)reconstruction,to establish a new margin assessment model,and to guide tumor bed delineation individually for radiotherapy.Methods:Thirty-three eligible patients undergoing BCS were recruited.The excision specimens was prepared with PMSS,and residual tumors were microscopically outlined,scanned and registered by PHOTOSHOP software.The 3D model of residual tumors was reconstructed with 3D-DOCTOR software to evaluate margin status and record pathological type,tumor length,3D negative margin distance.The gross tumor volume(GTV)was delineated based on clips placed in the lumpectomy cavity.CTV1 and CTV2 were defined by adding uniform 10mm and 15 mm margin based on GTV respectively;CTV3 and CTV4 were defined by adding 10mm and 15 mm margin based on 3D boundary of excision tumor respectively.Results:1.Based on the marginal assessment results of 3D pathological reconstruction,the rate of false negatives during the intraoperative rapid pathological examinationand postoperative routine pathological margin evaluation was 6.7%(2/30)and 3.5%(1/29),respectively.2.The pathological type of pathological large slice and routine pathological examination was consistent with rate of 93.9%(31/33).3.The measured tumor lengths of routine pathological and pathological 3D reconstruction were 19.00mm(10.00-45.00mm)and 20.00mm(7.00-49.00mm)(p=0.015),there was statistical difference between the two groups.4.The median volumes were 70.76cm~3(27.54-158.46cm~3)for CTV1,110.11cm~3(38.13-218.54cm~3)for CTV2,23.85cm~3(9.45-111.33cm~3)for CTV3,38.74cm~3 (15.57-162.67cm~3)for CTV4.There were statistical differences between CTV1 andCTV3,CTV2 and CTV4(P=0.000、0.000).Conclusions:The application of pathological 3D reconstruction technology can largely compensate for the shortcomings of the traditional margin assessment model,accurately determine the adjuvant treatment decisions after BCS,and guide the tumor bed delineation individually for radiotherapy.